Diaphragm for use in acoustic instruments



. July 9, 1929. c, MENKENS 1.720.524

DIAPHRAGM FOR USE IN'ACOUSTIG INSTRUMENTS Filed March 22, 1928 Patented July 9, 1929.

UNITED STATES PATENT OFFICE.

CYRIL MENKENS, 0F TEDDINGTON, ENGLAND.

DIAPHRAGM FOR USE IN ACOUSTIC INSTRUMENTS.

Application filed March 22, 1928, Serial No. 263,797, and in Great Britain March 28, 1927.

- The invention relates to diapltragms for use in acoustic reproducing or recording instruments, and method of manufacturing same, and it has for its object a construction of diaphragm of light weight and cheap to produce in that hand labor is verylargely eliminated.

According to the present invention a coneshaped diaphragm is formed of any suitable material suchasthin sheet aluminium or other metal; wood, celluloid, papier-mach or cardboard, a plurality of apertures of perforations of any suitable shape and size are then cut or formed therein. In order to strengthen and increase the rigidity of the remaining parts of the metal cone, ribs may be formed therein in any convenient manner.

To the diaphragm thus formed is then applied on one or both sides so as to be inte- "gral therewith, a covering of thin paper, silk or other suitable material.

In the accompanying drawing which illustrates this invention: Figure 1 is a plan of a diaphragm formed'in accordance with one embodiment of this invention. Figure 2 is a view partly in side elevation and partly in section on line 22 of Figure 1. Figure 3 is a section of a portion of a diaphragm on an enlarged scale showing the covering material applied to the inner surface thereof. Figure 4 is a view partly in side elevation andpartly in section of a modified method of formation: p

The diaphragm 1' as illustrated in Figures 1, 2 and 3 is formed of thin sheet metal pressed or formed into a conical shape, a plurality ofapertures 2, which may be of'any desired shape and size, are cut in the surface of the cone and in order to strengthen the remaining parts of the metal cone radial ribs 3 and concentric ribs 4 are preferably formed between the'apertures as shown. The ribs 3 and 4 may project on the exterior surface of the cone as shown or on the interior as desired.

.'-- The peripheral edge of the cone may be of channel formation as shown at 5 in Figures 1 and 2 or the edge may be wrapped around a fine wireor cane 6 as shown in Figure 3. The cone thus formed is covered on one or both sides with thin paper, silk or other material and subsequently treated with a suitable dope as shown at 7 in Figure 3.

"According to the modification illustrated in Figure 4, the diaphragm 1 is formed by first cutting out a circular disc, the flat disc is then pressed by suitably shaped dies into a cone shape the surplus metal being taken up by folding the sheet on itself in lines radiating from the centre thereby forming radial ribs as shown at 8, the concentric ribs 4 arranged between the aper' tures 2 may be formed by pressing or in any other convenient manner.

It will be obvious that the diaphragm or cone may be formed in various ways; for example, if made of aluminium, it may be cut out of a sheet of metal and the apertures stamped out while the sheet is in a flat state, or the cone may be spun, placed in a die and the apertures punched out and the strengthening ribs formed on the remaining parts in the one-operation. If the cone is made of celluloid or papier-lnach it may be moulded in a suitable press.

It will also be understood that while the diaphragm has been described and illustrated as being provided with radial ribs, the apertures in the diaphragm may be of a fancy shape and the ribs arranged in av spiral or other desired form.

What I claim is 1. A cone shaped diaphragm for use in acoustic instruments, comprising a perforated and ribbed disc of a thin and light material, and a covering of relatively lighter material applied thereto so as to cover the perforations in the disc...

2. A cone shaped diaphragm for use in acoustic instruments, composed of a frame of perforated and relatively thin material, means for strengthening the peripheral edge 'of said frame and'a covering of relatively thin material applied thereto so as to be integral therewith.

3. A cone shaped diaphragm for use in acoustic instruments, composed of a frame of perforated and relatively thin material, strengthening ribs formed on said frame, means for strengthening the peripheral. edge of said frame and a covering of relatively thin material applied thereto so as to be in' tegral therewith.

4. A cone shaped diaphragm for use in acoustic instruments, composed of a frame of perforated and relatively thin material, a

plurality of concentrically disposed strengthening ribs formed on said frame and a covering of relatively thin material applied thereto so as to be integral therewith.

5. A cone shaped diaphragm for use in acoustic instruments, composed of a frame of perforated and relatively thin material, means for strengthening the peripheral edge of said frame, a plurality of radially and concentrically disposed strengthening ribs formed on said frame and acovering of relatively thin material applied thereto so as to be integral therewith.

6. A cone shaped diaphragm for use in acoustic instruments, comprising a thin sheet metal frame perforated to integrally form a plurality of radially disposed members and a plurality of concentrically disposed members and a covering of relatively thin materialapplied thereto so as to be integral therewith.

7. A cone shaped diaphragm for use in acoustic instruments, comprising a thin sheet metal frame formed of a plurality of radially and concentrically disposed members integrally connected, means for strengthening saidradial and concentric members by pressing out the material of which said frame is formed, and a covering of relatively thin material applied thereto so as to be integral therewith. 4

a CYRIL MENKENS. 

